Laser doppler velocimeter

Abstract

A laser Doppler velocimeter is formed using erbium-doped fiber as the lasing medium. The fiber is diode-pumped. By properly modulating the lasing in the fiber, pulses of radiation may be generated. A telescope acts as the transmission device to focus the radiation at a specified point, and may also act as the receiving system for reflected radiation. The portion of the reflected radiation collected by the receiving system is analyzed to determine the Doppler shift caused by aerosols or objects at the focal point of the telescope.

1. A system for measuring atmospheric conditions comprising:
 a laser source comprising an optical wave guide formed from a single-mode optical fiber connected to an erbium-doped optical fiber amplifier formed in a ring or linear configuration for providing a beam of coherent laser radiation in the wave guide fiber, and 
 an output optical system for directing said beam of laser radiation to a region for measuring said atmospheric conditions. 
 
   
   
     2. A system according to  claim 1  wherein the wavelength of said beam of laser radiation is between 1.51 and 1.56 microns.